Urine
Overview
Urine is a typically sterile (in the absence of a disease condition) liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

 by-product of the body that is secreted by the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s through a process called urination
Urination
Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...

 and excreted through the urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...

. Cellular metabolism generates numerous by-products, many rich in nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

, that require elimination from the bloodstream. These by-products are eventually expelled from the body in a process known as micturition, the primary method for excreting water-soluble chemicals from the body.
Encyclopedia
Urine is a typically sterile (in the absence of a disease condition) liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

 by-product of the body that is secreted by the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s through a process called urination
Urination
Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...

 and excreted through the urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...

. Cellular metabolism generates numerous by-products, many rich in nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

, that require elimination from the bloodstream. These by-products are eventually expelled from the body in a process known as micturition, the primary method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...

.

Physiology

Most animals have excretory system
Excretory system
The excretory system is a passive biological system that removes excess, unnecessary or dangerous materials from an organism, so as to help maintain homeostasis within the organism and prevent damage to the body. It is responsible for the elimination of the waste products of metabolism as well as...

s for elimination of soluble toxic wastes. In humans, soluble wastes are excreted primarily by the urinary system
Urinary system
The urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder and the urethra.-Kidney:...

 and, to a lesser extent in terms of urea removed, by perspiration. The urinary system consists of the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s, ureter
Ureter
In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter....

s, urinary bladder
Urinary bladder
The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

, and urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...

. The system produces urine by a process of filtration
Filtration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...

, reabsorption, and tubular secretion. The kidneys extract the soluble wastes from the bloodstream, as well as excess water, sugars, and a variety of other compounds. The resulting urine contains high concentrations of urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 and other substances, including toxins. Urine flows from the kidney through the ureter, bladder, and finally the urethra before passing from the body.

Composition

Exhaustive detailed description of the composition of human urine can be found in NASA Contractor Report No. NASA CR-1802, D. F. Putnam, July 1971. That report provided detailed chemical analyses for inorganic and organic constituents, methods of analysis, chemical and physical properties and its behavior during concentrative processes such as evaporation, distillation and other physiochemical operations. Urine is an aqueous solution of greater than 95% water, with the remaining constituents, in order of decreasing concentration urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 9.3 g/L, chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...

 1.87 g/L, sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

 1.17 g/L, potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

 0.750 g/L, creatinine
Creatinine
Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...

 0.670 g/L and other dissolved ions, inorganic and organic compounds.

Urine is sterile
Sterilization (microbiology)
Sterilization is a term referring to any process that eliminates or kills all forms of microbial life, including transmissible agents present on a surface, contained in a fluid, in medication, or in a compound such as biological culture media...

 until it reaches the urethra where the epithelial cells lining the urethra are colonized by facultatively anaerobic Gram negative rods and cocci. Subsequent to elimination from the body, urine can acquire strong odors due to bacterial action, and in particular the release of asphyxiating ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 from the breakdown of urea. In medieval times clothes were stored in a garderobe
Garderobe
The term garderobe describes a place where clothes and other items are stored, and also a medieval toilet. In European public places, a garderobe denotes the cloakroom, wardrobe, alcove or an armoire. In Danish, Dutch, German and Spanish garderobe can mean a cloakroom. In Latvian it means checkroom...

 (literally 'to guard ones robes') close to the toilet shaft because this ammonia would kill the fleas. The term garderobe became a euphemism
Euphemism
A euphemism is the substitution of a mild, inoffensive, relatively uncontroversial phrase for another more frank expression that might offend or otherwise suggest something unpleasant to the audience...

 for toilet for that reason.

Some diseases alter the quantity and consistency of the urine, such as sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...

 as a consequence of diabetes. Beeturia
Beeturia
Beeturia is passing of red or pink urine after eating beets. It affects 10-14% of the population. While some believe it to be an autosomal recessive trait, it has been shown that individuals differ over time in having beeturia. Beeturia can appear and disappear in individuals...

, which affects some 10–14% of the population, results in the excretion of betanin
Betanin
Betanin, or Beetroot Red, is a red glycosidic food dye obtained from beets; its aglycone, obtained by hydrolyzing away the glucose molecule, is betanidin. As a food additive, its E number is E162. Betanin degrades when subjected to light, heat, and oxygen; therefore, it is used in frozen products,...

 after eating beets (such as beetroot
Beetroot
The beetroot, also known as the table beet, garden beet, red beet or informally simply as beet, is one of the many cultivated varieties of beets and arguably the most commonly encountered variety in North America, Central America and Britain.-Consumption:The usually deep-red roots of beetroot are...

) resulting urine with a pink/reddish color. Beeturia can appear and disappear in individuals.

Hazards

Urine is not toxic. However, being a waste product, it does contain compounds undesirable to the body and can be irritating to skin and eyes. After suitable processing (as is done, for example, on the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...

), it is possible to extract potable water from urine for drinking.

Characteristics

The typical color can range from clear to a dark amber, depending mostly upon the level of hydration of the body, among other factors.

Chemical analysis

Urine contains a range of substances that vary with what is introduced into the body. Aside from water, urine contains an assortment of inorganic salts and organic compounds, including proteins, hormones, and a wide range of metabolites.

Color

Urine is a transparent solution that can range from colorless to amber but is usually a pale yellow. In the urine of a healthy individual, the color comes primarily from the presence of urobilin
Urobilin
Urobilin is a yellow linear tetrapyrrole, resulting from the breakdown of heme, a cyclic tetrapyrrole.Urobilin is produced when Urobilinogen is oxidized by intestinal bacteria; it can also be...

. Urobilin in turn is a final waste product resulting from the breakdown of heme
Heme
A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. Not all porphyrins contain iron, but a substantial fraction of porphyrin-containing metalloproteins have heme as their prosthetic group; these are...

 from hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 during the destruction of aging blood cells.

Colorless urine indicates over-hydration, which is usually considered much healthier than dehydration (to some extent however over-hydration can remove essential salts from the body). In the context of a drug test, it could indicate a potential attempt to avoid detection of illicit drugs in the bloodstream through over-hydration.
  • Dark yellow urine is often indicative of dehydration.
  • Yellowing/light orange may be caused by removal of excess B vitamins from the bloodstream.
  • Certain medications such as rifampin and phenazopyridine
    Phenazopyridine
    Phenazopyridine is a chemical which, when excreted into the urine, has a local analgesic effect. It is often used to alleviate the pain, irritation, discomfort, or urgency caused by urinary tract infections, surgery, or injury to the urinary tract...

     can cause orange urine.
  • Bloody urine is termed hematuria
    Hematuria
    In medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal...

    , a symptom of a wide variety of medical conditions
  • Dark orange to brown urine can be a symptom of jaundice
    Jaundice
    Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...

    , rhabdomyolysis
    Rhabdomyolysis
    Rhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...

    , or Gilbert's syndrome
    Gilbert's syndrome
    Gilbert's syndrome , often shortened to GS, also called Gilbert-Meulengracht syndrome, is the most common hereditary cause of increased bilirubin and is found in up to 5% of the population...

    .
  • Black or dark-colored urine is referred to as melanuria and may be caused by a melanoma
    Melanoma
    Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...

    .
  • Fluorescent yellow / greenish urine may be caused by dietary supplemental vitamins, especially the B vitamins.
  • Consumption of beet
    Beet
    The beet is a plant in the Chenopodiaceae family which is now included in Amaranthaceae family. It is best known in its numerous cultivated varieties, the most well known of which is the purple root vegetable known as the beetroot or garden beet...

    s can cause urine to have a pinkish tint (beeturia
    Beeturia
    Beeturia is passing of red or pink urine after eating beets. It affects 10-14% of the population. While some believe it to be an autosomal recessive trait, it has been shown that individuals differ over time in having beeturia. Beeturia can appear and disappear in individuals...

    ), and asparagus
    Asparagus
    Asparagus officinalis is a spring vegetable, a flowering perennialplant species in the genus Asparagus. It was once classified in the lily family, like its Allium cousins, onions and garlic, but the Liliaceae have been split and the onion-like plants are now in the family Amaryllidaceae and...

     consumption can turn urine greenish.
  • Reddish or brown urine may be caused by porphyria
    Porphyria
    Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme bio-synthetic pathway . They are broadly classified as acute porphyrias and cutaneous porphyrias, based on the site of the overproduction and accumulation of the porphyrins...

    . Although again, the consumption of beets can cause the urine to have a harmless, temporary pink or reddish tint.

Odor

The smell of urine can be affected by the consumption of food. Eating asparagus is known to cause a strong odor in human urine. This is because of the body's breakdown of asparagusic acid
Asparagusic acid
Asparagusic acid, S22CHCO2H is an organosulfur carboxylic acid present in the vegetable asparagus and may be the metabolic precursor to other odorous thiol compounds. Biosynthetic studies revealed that asparagusic acid is derived from isobutyric acid. This colorless solid has a m.p. of 75.7-76.5...

. Other foods and beverages that contribute to odor include saffron
Saffron
Saffron is a spice derived from the flower of Crocus sativus, commonly known as the saffron crocus. Crocus is a genus in the family Iridaceae. Each saffron crocus grows to and bears up to four flowers, each with three vivid crimson stigmas, which are each the distal end of a carpel...

, alcohol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

, coffee
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...

, turkey, and onion
Onion
The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...

. Particularly spicy foods can have a similar effect, as the compounds are not broken down by the kidneys and pass through the body in the urine.

Turbidity

Turbid
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....

 (cloudy) urine may be a symptom of a bacterial infection, but can also be caused by crystallization of salts such as calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....

.

pH

The pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 of urine is close to neutral (7) but can normally vary between 4.6 and 8. In persons with hyperuricosuria
Hyperuricosuria
Hyperuricosuria is a medical term referring to the presence of excessive amounts of uric acid in the urine. Notable direct causes of hyperuricosuria are dissolution of uric acid crystals in the kidneys or urinary bladder, and hyperuricemia...

, acidic urine can contribute to the formation of stones
Calculus (medicine)
A calculus is a stone that forms in an organ or duct of the body. Formation of calculi is known as lithiasis...

 of uric acid
Uric acid
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates such as ammonium acid urate. Uric acid is created when the body breaks down purine nucleotides. High blood concentrations of uric acid...

 in the kidneys, ureters, or bladder. Urine pH can be monitored by a physician or at home.

A diet high in citrus, vegetables, or dairy can increase urine pH (more basic). Some drugs also can increase urine pH, including acetazolamide, potassium citrate, and sodium bicarbonate.

A diet high in meat can decrease urine pH (more acidic). Cranberries, popularly thought to decrease the pH of urine, have actually been shown not to acidify urine. Drugs that can decrease urine pH include ammonium chloride
Ammonium chloride
Ammonium chloride NH4Cl is an inorganic compound with the formula NH4Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of natural, mineralogical form of ammonium chloride...

, chlorothiazide diuretics, and methenamine mandelate.

Volume

The amount of urine produced depends on numerous factors including level of hydration, activities, environmental factors, weight of individual, and the individual's health. In adult humans the average production is about 1 – 2 L per day. Producing too much or too little urine needs medical attention: Polyuria
Polyuria
Polyuria is a condition usually defined as excessive or abnormally large production or passage of urine . Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom...

 is a condition of excessive production of urine (> 2.5 L/day), in contrast to oliguria
Oliguria
Oliguria is the low output of urine, It is clinically classified as an output below 300-500ml/day. The decreased output of urine may be a sign of dehydration, renal failure, hypovolemic shock, HHNS Hyperosmolar Hyperglycemic Nonketotic Syndrome, multiple organ dysfunction syndrome, urinary...

 where < 400 mL are produced per day, or anuria
Anuria
Anuria means nonpassage of urine, in practice is defined as passage of less than 50 milliliters of urine in a day. Anuria is often caused by failure in the function of kidneys. It may also occur because of some severe obstruction like kidney stones or tumours. It may occur with end stage renal...

 with a production of < 100 mL per day.

Density or specific gravity

Normal urine density or specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

 values vary between 1.003–1.035 (g·cm−3) , and any deviations may be associated with urinary disorders.

Urine in medicine

Examination

Many physicians in history have resorted to the inspection and examination of the urine of their patients. Hermogenes
Hermogenes
Hermogenes is a Greek name . It may refer to:* Hermogenes , Attic Greek potter* Hermogenes , Greek* Hermogenes of Priene , Greek architect...

 wrote about the color and other attributes of urine as indicators of certain diseases. Abdul Malik Ibn Habib of Andalusia
Andalusia
Andalusia is the most populous and the second largest in area of the autonomous communities of Spain. The Andalusian autonomous community is officially recognised as a nationality of Spain. The territory is divided into eight provinces: Huelva, Seville, Cádiz, Córdoba, Málaga, Jaén, Granada and...

 d.862 AD, mentions numerous reports of urine examination throughout the Umayyad
Umayyad
The Umayyad Caliphate was the second of the four major Arab caliphates established after the death of Muhammad. It was ruled by the Umayyad dynasty, whose name derives from Umayya ibn Abd Shams, the great-grandfather of the first Umayyad caliph. Although the Umayyad family originally came from the...

 empire. Diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

 got its name because the urine is plentiful and sweet. A urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...

 is a medical examination of the urine and part of routine examinations. A culture of the urine is performed when a urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...

 is suspected. A microscopic examination of the urine may be helpful to identify organic or inorganic substrates and help in the diagnosis.

The color and volume of urine can be reliable indicators of hydration level. Clear and copious urine is generally a sign of adequate hydration, dark urine is a sign of dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

. The exception occurs when alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

, caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

, or other diuretics are consumed, in which case urine can be clear and copious and the person still be dehydrated.

Resource

Urine contains proteins and other substances that are useful for medical therapy and are ingredients in many prescription drugs (e.g., Ureacin, Urecholine, Urowave). Urine from postmenopausal
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...

 women is rich in gonadotropin
Gonadotropin
Gonadotropins are protein hormones secreted by gonadotrope cells of the pituitary gland of vertebrates. This is a family of proteins, which include the mammalian hormones follitropin , lutropin , placental chorionic gonadotropins hCG and eCG and chorionic gonadotropin , as well as at least two...

s that can yield follicle stimulating hormone and luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...

 for fertility therapy. The first such commercial product was Pergonal. Urine from pregnant women contains enough human chorionic gonadotropin
Human chorionic gonadotropin
Human chorionic gonadotropin or human chorionic gonadotrophin is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast .. Some tumors make this hormone; measured elevated levels when the patient is not...

s for commercial extraction and purification to produce hCG medication. Pregnant mare urine is the source of estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

s, namely Premarin
Premarin
Premarin is the commercial name for a compound cream of vaginally administered estrogens, consisting primarily of conjugated estrogens. Isolated from mares' urine , it is manufactured by Wyeth Pharmaceuticals and has been marketed since 1942...

. Urine also contains antibodies, which can be used in diagnostic antibody tests for a range of pathogens, including HIV-1.

Agriculture

Urine contains large quantities of nitrogen (mostly as urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

), as well as significant quantities of dissolved phosphates and potassium, the main macronutrients required by plants. Diluted at least 8:1 with water it can be applied directly to soil as a fertilizer. Undiluted, it can chemically burn the roots of some plants, but it can be safely used as a source of complementary nitrogen in carbon rich compost
Compost
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...

.
Urine typically contains 70% of the nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 and more than half the phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 and potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

 found in urban waste water flows, while making up less than 1% of the overall volume. Thus far, source separation, or urine diversion
Urine diversion
-Urine diversion:Urine diversion refers to the separation of urine from feces at the point source, i.e at the toilet or outhouse. A toilet fixture used to help facilitate the separation is called a urine diversion toilet or UDT. The bowel has two separate compartments which may or may not be...

 and on-site treatment has been implemented in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, and Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 among other countries with the Bill and Melinda Gates Foundation provided some of the funding implemenations. China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 – in 2003 reportedly had 685,000 operating source separation toilets spread out among 17 provinces

"Urine management" is a relatively new way to view it and close the cycle of agricultural nutrient flows, to reduce sewage treatment costs, reduce ecological consequences such as eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...

, and reduce the influx of nutrient rich effluent into aquatic or marine ecosystems.
The fertilization effect of urine has been found to be comparable to that of commercial fertilizers with an equivalent NPK rating
NPK rating
NPK rating is used to label fertilizer based on the relative content of the chemicals nitrogen, phosphorus, and potassium that are commonly used in fertilizers....

.
However, depending on the diet of the producer, urine may also have undesirably high concentrations of various inorganic salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

s such as sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

, which are also excreted by the renal system. Concentrations of heavy metals such as lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

, mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

, and cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...

, commonly found in solid human waste, are much lower in urine (though not low enough to qualify for use in organic agriculture under current EU rules).
Proponents of urine as a natural source of agricultural fertilizer claim the risks to be negligible or acceptable. Their views seem to be backed by research showing there are more environmental problems when it is treated and disposed of compared with when it is used as a resource.

It is unclear whether source separation, urine diversion
Urine diversion
-Urine diversion:Urine diversion refers to the separation of urine from feces at the point source, i.e at the toilet or outhouse. A toilet fixture used to help facilitate the separation is called a urine diversion toilet or UDT. The bowel has two separate compartments which may or may not be...

, and on-site treatment of urine can be made cost effective, and to what degree the required behavioral changes would be regarded as socially acceptable, as the largely successful trials performed in Sweden may not readily generalize to other industrialized societies. In developing countries, the application of pure urine to crops is rare, but the use of whole raw sewage (termed night soil
Night soil
Night soil is a euphemism for human excrement collected at night from cesspools, privies, etc. and sometimes used as a fertilizer. Night soil is produced as a result of a waste management system in areas without community infrastructure such as a sewage treatment facility, or individual septic...

) has been common throughout history. However, there are more calls for urine's use as a fertilizer such as a Scientific American article "Human urine is an effective fertizler".

Cleaning

In pre-industrial use as a cleaning fluid due to its ammonia content.

Munitions

Urine has been used in the manufacture of gunpowder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

. Urine, a nitrogen source, was used to moisten straw or other organic material, which was kept moist and allowed to rot for several months to over a year. The resulting salts were washed from the heap with water, which was evaporated to allow collection of crude saltpeter crystals, that were usually refined before being used in making gunpowder.

Survival uses

Numerous survival instructors and guides, including the US Army Field Manual, advise against drinking urine for survival. These guides explain that drinking urine tends to worsen, rather than relieve dehydration due to the salts in it, and that urine should not be consumed in a survival situation, even when there is no other fluid available. In hot weather survival situations, where water is also hard to find, soaking cloth in urine (a shirt for example) and putting it on one's head can help cool the body.

During World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, the Germans
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

 experimented with numerous poisonous gases for use during war. After the first German chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 gas attacks, Allied troops were supplied with masks of cotton pads that had been soaked in urine. It was believed that the ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 in the pad neutralized the chlorine. These pads were held over the face until the soldiers could escape from the poisonous fumes, although it is now known that chlorine gas reacts with urine to produce toxic fumes
Chloramine
Chloramines are derivatives of ammonia by substitution of one, two or three hydrogen atoms with chlorine atoms. Monochloramine is an inorganic compound with the formula NH2Cl. It is an unstable colourless liquid at its melting point of -66° temperature, but it is usually handled as a dilute...

 (see chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 and Use of poison gas in World War I).

Urban myth states that urine works well against jellyfish
Jellyfish
Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...

 stings, and this scenario was demonstrated on a Season 4 episode of the NBC-TV show Friends
Friends
Friends is an American sitcom created by David Crane and Marta Kauffman, which aired on NBC from September 22, 1994 to May 6, 2004. The series revolves around a group of friends in Manhattan. The series was produced by Bright/Kauffman/Crane Productions, in association with Warner Bros. Television...

, "The One With the Jellyfish", an early episode of the CBS-TV show Survivor
Survivor (U.S. TV series)
Survivor is an American version of the Survivor reality television game show, itself derived from the Swedish television series Expedition Robinson originally created in 1997 by Charlie Parsons. The series premiered on May 31, 2000 on CBS...

and the documentary film The Real Cancun
The Real Cancun
The Real Cancun is a 2003 American reality film released on April 25, 2003 in the U.S.Inspired by the reality television genre, this film followed the lives of sixteen Americans from March 13 - 23, 2003 as they celebrated spring break in Cancún, Mexico and experienced romantic relationships,...

. At best, it is ineffective and in some cases this treatment may make the injury worse.

Tanning

Tanners soaked animal skins in urine to remove hair fibers—a necessary step in the preparation of leather.

Textiles

Urine has often been used as a mordant
Mordant
A mordant is a substance used to set dyes on fabrics or tissue sections by forming a coordination complex with the dye which then attaches to the fabric or tissue. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations. The term mordant comes from the Latin...

 to help prepare textiles, especially wool, for dyeing. This usage was mentioned in Gathering Blue
Gathering Blue
Gathering Blue is a 2000 children's, social science fiction, dystopian novel by noted children's author Lois Lowry. The book is a companion novel to The Giver , and is followed by Messenger in The Giver trilogy. It is set in the same future time period and it treats some of the same themes...

by Lois Lowry
Lois Lowry
Lois Lowry is an American author of children's literature. She began her career as a photographer and a freelance journalist during the early 1970s...

. In Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, the process of "walking" (stretching) the tweed
Tweed (cloth)
Tweed is a rough, unfinished woolen fabric, of a soft, open, flexible texture, resembling cheviot or homespun, but more closely woven. It is made in either plain or twill weave and may have a check or herringbone pattern...

 is preceded by soaking in urine.

History and language

Ancient Romans
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 used human urine to cleanse grease stains from their clothing, before acquiring soap
Soap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...

s from the Germans
Germanic peoples
The Germanic peoples are an Indo-European ethno-linguistic group of Northern European origin, identified by their use of the Indo-European Germanic languages which diversified out of Proto-Germanic during the Pre-Roman Iron Age.Originating about 1800 BCE from the Corded Ware Culture on the North...

 during the first century AD. Urine that has been fermented for the purposes of cleaning is referred to as lant
Lant
Lant is an Old English word for aged urine. Collected urine was put aside to ferment until used in many pre-industrial processes, for cleaning floors and making gunpowder among other things, because of its chemical attributes.-History:...

. The emperor Nero
Nero
Nero , was Roman Emperor from 54 to 68, and the last in the Julio-Claudian dynasty. Nero was adopted by his great-uncle Claudius to become his heir and successor, and succeeded to the throne in 54 following Claudius' death....

 instituted a tax on the urine industry. This tax was continued by Nero's successor, Vespasian
Vespasian
Vespasian , was Roman Emperor from 69 AD to 79 AD. Vespasian was the founder of the Flavian dynasty, which ruled the Empire for a quarter century. Vespasian was descended from a family of equestrians, who rose into the senatorial rank under the Emperors of the Julio-Claudian dynasty...

, to whom is attributed the Latin saying Pecunia non olet
Pecunia non olet
Pecunia non olet is a Latin saying. The phrase is ascribed to the Roman emperor Vespasian .-History:...

(money doesn't smell) – this is said to have been Vespasian's reply to a complaint from his son
Titus
Titus , was Roman Emperor from 79 to 81. A member of the Flavian dynasty, Titus succeeded his father Vespasian upon his death, thus becoming the first Roman Emperor to come to the throne after his own father....

 about the disgusting nature of the tax. Vespasian's name is still attached to public urinals in France (vespasiennes), Italy (vespasiani), and Romania (vespasiene).

Alchemists
Alchemy
Alchemy is an influential philosophical tradition whose early practitioners’ claims to profound powers were known from antiquity. The defining objectives of alchemy are varied; these include the creation of the fabled philosopher's stone possessing powers including the capability of turning base...

 spent much time trying to extract gold from urine, and this effort led to discoveries such as white phosphorus, which was discovered by the German alchemist Hennig Brand
Hennig Brand
Hennig Brand was a merchant and alchemist in Hamburg, Germany. He discovered phosphorus around 1669.-Early life:The circumstances of Brand's birth are unknown. Some sources describe his origins as humble and indicate that he had been an apprentice glass-maker as a young man...

 in 1669 when he was distilling fermented
Fermentation (biochemistry)
Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...

 urine. In 1773 the French chemist Hilaire Rouelle
Hilaire Rouelle
Hilaire Marin Rouelle was a French chemist. Commonly cited as the 1773 discoverer of urea, he was not the first to do so. Dutch scientist Herman Boerhaave had discovered this chemical as early as 1727. Rouelle is known as "le cadet" to distinguish him from his older brother, Guillaume-François...

 discovered the organic compound urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 by boiling urine dry.

The word "urine" was first used in the 14th century. Before that, the concept was described by the now vulgar word "piss". Onomatopoetic in origins, "piss" was the primary means of describing urination, as "urinate" was at first used mostly in medical contexts. Likely, "piss" became vulgar through its use by lower class characters such as the reeve and the Wife of Bath in Geoffrey Chaucer's
Geoffrey Chaucer
Geoffrey Chaucer , known as the Father of English literature, is widely considered the greatest English poet of the Middle Ages and was the first poet to have been buried in Poet's Corner of Westminster Abbey...

 14th century work The Canterbury Tales
The Canterbury Tales
The Canterbury Tales is a collection of stories written in Middle English by Geoffrey Chaucer at the end of the 14th century. The tales are told as part of a story-telling contest by a group of pilgrims as they travel together on a journey from Southwark to the shrine of Saint Thomas Becket at...

. "Piss" and its association with vulgarity has led to its current classification as obscene, as well as its use in such colloquial expressions as "to piss off" and "piss poor". Euphemism
Euphemism
A euphemism is the substitution of a mild, inoffensive, relatively uncontroversial phrase for another more frank expression that might offend or otherwise suggest something unpleasant to the audience...

s such as "pee" are used, but there are many more for the act of urination.

See also

  • Amniotic fluid
    Amniotic fluid
    Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...

  • Bed-Wetting
  • Drinking urine
  • Ecological sanitation
    Ecological sanitation
    Ecological sanitation, also known as ecosan or eco-san, are terms coined to describe a form of sanitation that usually involves urine diversion and the recycling of water and nutrients contained within human wastes back into the local environment....

  • Lant
    Lant
    Lant is an Old English word for aged urine. Collected urine was put aside to ferment until used in many pre-industrial processes, for cleaning floors and making gunpowder among other things, because of its chemical attributes.-History:...

  • Urination
    Urination
    Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...

  • Urine therapy
    Urine therapy
    In alternative medicine, the term urine therapy refers to various applications of human urine for medicinal or cosmetic purposes, including drinking of one's own urine and massaging one's skin with one's own urine...

  • Urolagnia
    Urolagnia
    Urolagnia is a paraphilia in which sexual excitement is associated with the sight or thought of urine or urination. The term has origins in the Greek Language .Those who enjoy urolagnia may enjoy urinating on another person or persons, or being urinated upon...

    , an attraction to urine

Further reading

  • Definition of oliguria and anuria
  • Hermogenes on urine
  • “Urine.” Oxford English Dictionary. October 29, 2008 OED.com
  • Geoffrey Chaucer, Department of English. Dept. home page. October 3, 2006. Harvard University
    Harvard University
    Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

     October 27, 2008 Harvard.edu


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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